FIGS. 8(a) and 8(b) are views illustrating prior art array type semiconductor laser devices.
In the array type semiconductor laser device shown in FIG. 8(a), reference numeral 3000 designates a submount, and a semiconductor laser array body 1000 is mounted on the submount 3000. Each semiconductor laser constituting the semiconductor laser array includes an active layer 2000.
In the array type semiconductor laser device shown in FIG. 8(b), reference numeral 6000 designates a submount, and a plurality of semiconductor laser bodies, five laser bodies in this case, 4000 are mounted vertically on the submount 6000. Each semiconductor laser body 4000 includes an active layer 5000. The semiconductor laser body 4000 and the submount 6000, and the semiconductor laser bodies 4000 are adhered to each other with solder.
The prior art array type semiconductor laser devices have structures as described above. For example, in the prior device shown in FIG. 8(a), since a region R1, a light emitting region including the active layers, is extended in proportion to the number of the semiconductor laser bodies, light cannot be concentrated on a narrow region.
In addition, in the prior device shown in FIG. 8(b), a region R2 serving as a light emitting region of the semiconductor laser device can be made narrower than the region R1 shown in FIG. 8(a). However, when the semiconductor laser body 4000 and the submount 6000, and the semiconductor laser bodies 4000 are adhered to each other with solder, a method of successively adhering using a plurality of solders having the different melting points is used in order not to melt the adhered portions again due to the following soldering. Therefore, more kinds of solder which are used for adhering are required as the number of the semiconductor laser bodies increases, whereby the damage due to the heat in the adhering process is made worse. In addition, since each element is small, it is difficult to mount the elements, whereby the slippage of the elements in an optical axis direction is caused when the semiconductor laser bodies are laminated.
Further, when the prior art array type semiconductor laser devices shown in FIGS. 8(a) and 8(b) are used as a light source of a radar which is mounted on an automobile or the like and is used for perceiving obstacles, higher density and higher output of the respective semiconductor lasers are required. For example, a current value of about 100 mA which is usually used in the array type semiconductor laser device needs to be increased to about 10 A though it is pulsed. In this time, in the prior device shown in FIG. 8(a), for example, when a current which is supplied to one semiconductor laser is 100 mA, more current is required depending upon the number of the semiconductor lasers. Therefore, if the power source can not supply all of the required current, the array type semiconductor laser device does not operate.
In the prior device shown in FIG. 8(b), for example, when a voltage applied to one semiconductor laser is 2 V, it is required that the voltage be increased for the number of the semiconductor lasers since it is applied to the whole array type semiconductor laser device. Therefore, if the power source can not supply all of the required voltage, the array type semiconductor laser device does not operate.